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use i2c::{I2C, TransDir};
const AT24C_ADDR: u8 = 0b1010111; /* suppose A0, A1, A2 = 1 */
pub struct AT24C<'a>(&'a I2C<'a>);
impl<'a> AT24C<'a> {
pub fn new(i2c: &'a I2C<'a>) -> AT24C<'a> {
AT24C(i2c)
}
pub fn read(&self, start: u16, size: usize, buf: &mut [u8]) {
let &AT24C(ref i2c) = self;
i2c.conf_ack(true); /* enable ack */
i2c.start(true, true); /* start condition (for writing addr) */
while !i2c.send_addr(AT24C_ADDR, TransDir::TRANSMITTER, true) {
i2c.start(true, true);
}
i2c.send(((start >> 8) & 0x0f) as u8, true); /* first word addr */
i2c.send((start & 0xff) as u8, true); /* second word addr */
i2c.start(true, true); /* restart to read */
i2c.send_addr(AT24C_ADDR, TransDir::RECEIVER, true);
for i in 0..(size - 1) {
buf[i] = i2c.recv(true);
}
i2c.conf_ack(false); /* nack */
buf[size - 1] = i2c.recv(true);
i2c.stop(true);
}
pub fn page_write(&self, start: u16, size: usize, buf: &[u8]) {
let &AT24C(ref i2c) = self;
i2c.conf_ack(true); /* enable ack */
i2c.start(true, true); /* start condition (for writing addr) */
while !i2c.send_addr(AT24C_ADDR, TransDir::TRANSMITTER, true) {
i2c.start(true, true);
}
i2c.send(((start >> 8) & 0x0f) as u8, true); /* first word addr */
i2c.send((start & 0xff) as u8, true); /* second word addr */
for i in 0..size {
i2c.send(buf[i], true);
}
i2c.stop(true);
}
pub fn write(&self, start: u16, size: usize, buf: &[u8]) {
let end = start + size as u16 - 1;
let pg_s_off = start & 0x1f;
let pg_e_off = end & 0x1f;
let pg_s = start >> 5;
let pg_e = end >> 5;
if pg_s == pg_e {
self.page_write(start, size, buf);
} else {
let mut buf = buf;
self.page_write(start, (0x20 - pg_s_off) as usize, buf);
buf = &buf[0x20 - pg_s_off as usize..];
for i in (pg_s + 1)..pg_e {
self.page_write(i << 5, 0x20, buf);
buf = &buf[0x20..];
}
self.page_write(pg_e << 5, (pg_e_off + 1) as usize, buf);
}
}
}
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